B1

Describe the genetic material in a prokaryotic cell and a eukaryotic cell

Eukaryotic cells have a cell membrane, a cytoplasm and a nucleus containing the genetic material

2 of 18

What are plasmids?

Plasmids are fragments of double-stranded DNA that can be used to study and manipulate genetic elements.

3 of 18

state three extra organelles that are found in plant cells but not animal cels and describe their functions

A cell wall which which strengthens the cell, A vacuole which is filled with cell sap and chloroplasts which absorb light energy to make food

4 of 18

A yeast cell has a cell membrane, cell wall, a nucleus and a cytoplasm. Is it prokaryotic or eukaryotic?

Eukaryotic because their cells have a nucleus

5 of 18

Explain the function of a ribosome

The primary function of ribosomes is synthesis of proteins according to the sequence of amino acids as specified in the messenger RNA.

6 of 18

describe how the structure of a nerve cell helps its function

the function of nerve cells is to transmit electrical messages and signals throughout the body

7 of 18

describe how the structure of a xylem cell helps its function

Xylem vessels are made up of hollow cells designed to carry water and minerals from the roots of a plant to the trunk, with altered cell walls to allow for the passage of one vessel to another.

8 of 18

Defin the term "resolution"

resolution is sharpness. it is the ability of the lens to distingush between two points clearly.

9 of 18

State one advantage and one disadvantage of using a light microscope

One advantage is that light microscopes can allow you to view living specimens but a disadvantage is that the wavelength of the light waves that illuminate the specimen limits the resolution

10 of 18

State one advantage and one disadvantage of using an electron microscope

an advantage of using an electron microscope is that it has the ability to produce a more powerful magnification than the light microscope, however a disadvantage would be that Electron microscopes are very expensive and are not portable

11 of 18

The diameter of a human capillary was measured on a micrograph. The image measure 5mm and the magnification is x1000. What is the actual diameter of the capillary?

0.005 (5 divided by 1000)

12 of 18

Define the terms chromosome, gene and DNA

chromosome:a thread-like structure of nucleic acids and protein found in the nucleus of most living cells, Gene: A unit of heredity which is transferred from a parent to offspringDNA is the complex chemical that carries genetic information

13 of 18

Describe the factors that affect the rate of diffusion

The temperature and the concentration gradient

14 of 18

why can't multicellular organisms rely on simple diffusion?

As the size of an organism increases, its surface area to volume ratio decreases meaning it has less surface area available for substances to diffuse through, so the rate of diffusion isn't fast enough to meet its cells requirements

15 of 18

define the term osmosis and a semi-permeable membrane

Osmosis: the movement of water molecules from an area of high water concentration to an area of low water concentration, semi permeable membrane: A type of membrane that will allow certain molecules/ions to pass through it by diffusion

16 of 18

give an example of active transport in plants and humans

Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants.

17 of 18

explain the differences between diffusion, osmosis and active transport

Active transport requires energy ( ATP molecules ), while osmosis and diffusion require a concentration difference between the cell and its surrounding